During many medical procedures, fixation elements such as screws may be used to affix certain devices, such as implants, to an underlying structure such as bone or even another implant. In certain vertebral fixation procedures, once fixation members have securely attached an implant to the underlying structure, a blocking plate is affixed to the implant using a screw to thereby prevent the fixation members from backing out of the implant. For example, the blocking plate can be attached to an intervertebral implant after the implant has been affixed to a superior vertebral body and an inferior vertebral body using one or more fixation members. Such screws are typically affixed using drivers that securely hold the screw so as to prevent the screw from inadvertently falling into the patient prior to the placement of the screw.
Devices for retaining screws on a screw driver are known, but many of the prior devices depend on a linear side-bearing force from a clamp or other mechanism to hold the screw in place. Other methods of temporarily retaining a screw to a driver include using a central threaded rod down the center of the driver or a driver with a spring-wire off axis of the driver that may protrude laterally into the screw.